Packaging

ABSTRACT

The invention relates to packages for materials or the mixture thereof, in particular for perishable products such as food or pharmaceutical products. The aim of said invention is to deliver means to make it possible to check the state of said for materials or the mixture thereof without destroying the package thereof. For this purpose, the inventive packaging comprises an optically sensitive element which is embodied in the form of a sensitive membrane or film or exhibits the properties thereof. As a result, the specific variations of the film thicknesses, scattered light variations, optical refractive index and spectral variations are used.

This invention relates to packages for substances or mixtures of substances, in particular perishable goods such as foods or drugs.

It is intended to open up possibilities for checking the content of the package without destroying the latter. For example, a possibility should be provided for checking foods which are contained in packages as to whether they can still be consumed or their state has deteriorated such that they can result in damage to organisms.

It is hitherto customary to print expiration dates on packages or to take samples of the ingredients out of a package at certain places and subject them to a subsequent external analysis. In the last-named case it is necessary to open the package or at least make a small opening which cannot always be completely closed after sampling.

It is therefore the problem of the invention to propose a possibility for checking the state of substances or mixtures of substances contained in packages without destroying the package.

According to the invention, an optically readable sensitive element is therefore contained within the package.

The optically sensitive element used here may be a sensitive layer or membrane alone or such a membrane or layer attached to the sensitive element.

Thus, such a membrane or layer can change its layer thickness, refractive index, scattered light properties as well as spectral properties in the UV, VIS, NIR, IR through corresponding physical and/or chemical state changes within the package, but also time-dependently, and the particular change then be used as a measure of the particular state.

By optical means for example, one or simultaneously several such changes can be determined by means of interferometry, spectroscopy but also by surface plasmon resonance.

Layer thickness changes can occur for example dependently on concentration. Thus, an oxygen concentration, the hydrocarbon concentration, the hydrogen concentration or water contained within the package can affect the layer thickness, for example by reversible swelling.

In some cases, however, a temperature- or pressure-dependent change can also lead to layer thickness changes.

It is also possible to use per se known membranes or layers containing or exhibiting one or more dyes or selective markers. Such dyes or markers can luminesce, for example, and a state-dependent change in intensity, phase or decay time of luminescence can be used as a measure of the state of substances or mixtures of substances contained in packages.

For example, it is known that certain luminescence dyes luminesce to varying degrees under the influence of oxygen in dependence on the concentration thereof or the oxygen partial pressure, or the luminescence decay time behavior changes accordingly, so that this can be utilized with an optical detector from outside upon simultaneous or sequential irradiation with a light source emitting light in a: wavelength range exciting luminescence.

The invention can also be used to detect changing pH values within the package.

It is possible to immobilize or fix a sensitive membrane or layer directly onto the inner wall of the package, possibly using for example a transparent adhesive film which can be bonded into the package.

The membrane or layer can also be attached or fixed on a separate element which is for example fixed in a frame, and said frame can in turn be connected to the package.

In some cases, and with suitable substances or mixtures of substances contained in packages, it is also possible to simply insert sensitive elements into the package.

Further, the sensitive element can be directly part of the package, for example by bonding or welding, or be the package itself.

For detection by optical means, at least a partial area of an inventive package should be transparent for the measurement procedure, for example optically in the corresponding wavelength range, or have a transparent window. This permits for example a color change occurring because of a fault or a leak in the package to be readily recognized from outside.

The layers or membranes can be provided with optical, mechanical or chemical protective layers to prevent undesirable influences on the layers or membranes.

Such protective layers should if possible be permeable to substances to be detected, which can be achieved for example by accordingly thin metal layers. Such thin metal layers, preferably consisting of noble metals, particularly preferably of silver, provide protection from extraneous light and moisture, but are still sufficiently permeable to many gases if accordingly thin.

Further, information can be applied. It can comprise for example calibrating data, batch numbers.

Said information can also be transmitted by a radio frequency identification (RFI) chip mounted on the membrane/layer.

Extending the membrane/layer by an integrated, compact evaluation unit permits direct processing of the measuring signals. Said evaluation unit can be supplied with energy or transfer the signals (measuring data/control commands) for example by means of electromagnetic waves.

With aggressive media, protective layers of PTFE or PTFE-based layers can be formed on membranes or layers.

Further, protective layers can advantageously be made of dielectric material. For example, a SiO2 sol-gel is to be stated here.

Further, it is possible to construct protective layers from optically reflective or absorbent lacquer layers, preferably based on synthetic resin lacquers or acrylic lacquers.

It is also possible to dispose a plurality of such layers one above the other.

A calibration of the sensitive elements can be done when the package is being closed by adjusting specific pressures, a vacuum and a corresponding excess pressure being adjustable.

It is also possible to perform a selective supply of a calibrating gas of known gas composition or supply of calibrating liquid or a temperature variation for calibration.

Calibration can also already be done before the sensitive element is incorporated into the package. For this purpose it is possible to use an external calibrating module in which defined changes of the measurand, for example defined pressure changes, can be adjusted.

The inventive solution can be used to carry out a monitoring of the substances or mixtures of substances contained in packages repeatedly over long time periods, without there being any possible influence of the environment from outside into the package.

The monitoring can correspondingly be carried out over the entire transport and storage chain up to the final consumer, so that increased consumer protection is attainable.

It is unnecessary to take samples from the package, and no corresponding additional sampling elements are required for this purpose.

For detection of the state it is possible to use per se known, preferably optical, measuring technology, which can for example be placed against a transparent area of the particular package from outside.

It is thus possible that a suitable optical system with a light source whose light is guided for example by a flexible optical waveguide is placed against the particular package from outside and the light of the light source directed onto a membrane or layer, and an optical change occurring on or in the layer can be directed onto an optical detector for example by said optical waveguide or a further optical waveguide.

A measuring head from which excitation light and/or reflected or emitted light can be directed onto the optical detector should be so formed that the influence of scattered light is at least reduced or constant. 

1. A package for substances or mixtures of substances, characterized in that the package contains an optically sensitive element.
 2. The package according to claim 1, characterized in that a sensitive membrane or layer is present on the sensitive element or is the sensitive element.
 3. The package according to claim 2, characterized in that the membrane or layer is subject to specific layer thickness changes, scattered light changes, changes of optical refractive index, spectral changes.
 4. The package according to claim 3, characterized in that the layer thickness changes can be measured by the method of interferometry, surface plasmon resonance, spectroscopy.
 5. The package according to claim 3, characterized in that the layer thickness change is effected dependently on one of oxygen concentration, hydrocarbon concentration, hydrogen concentration, H₂O content, and dependently on temperature or pressure.
 6. The package according to claim 2, characterized in that the membrane or layer contains one or more dyes or selective markers.
 7. The package according to claim 2, characterized in that state changes within the package are detectable by surface plasmon resonance, spectroscopy or luminescence changes on the membrane or layer.
 8. The package according to claim 1, characterized in that a marker or dye is changeable dependently on concentration (pH, O₂) or dependently on temperature or pressure.
 9. The package according to claim 1, characterized in that a detection is effected through the package without damaging the same.
 10. The package according to claim 2, characterized in that the membrane or layer is applied directly to the inner side of the package.
 11. The package according to claim 2, characterized in that the membrane or layer is fixed to an adhesive film adapted to be bonded into the package.
 12. The package according to claim 2, characterized in that the membrane or layer is connected to the package on or in a transparent element which is also fixable in a frame.
 13. The package according to claim 1, characterized in that the sensitive element is inserted into the package.
 14. The package according to claim 2, characterized in that calibration of the sensitive layer or membrane can be effected upon closing by at least one of vacuum or excess pressure, supply of gas, supply of calibrating liquid and temperature variation.
 15. The package according to claim 2, characterized in that a calibration of the sensitive layer or membrane can be effected by an external calibration before incorporation into the package.
 16. The package according to claim 15, characterized in that an external calibrating module is adapted to be calibrated by pressure changes.
 17. The package according to claim 2, characterized in that a sensitive membrane or layer has at least one of an optical, mechanical and chemical protective layer applied thereto.
 18. The package according to claim 17, characterized in that the protective layers are formed of by one of permeable metal, dielectric, PTFE or PTFE-base layers.
 19. The package according to claim 17, characterized in that the protective layers are formed of at least one of reflective and absorbent layers, in particular based on at least one of synthetic resins and acrylic.
 20. The package according to claim 1, characterized in that the package is transparent to electromagnetic waves or has a window transparent to electromagnetic waves.
 21. The package according to claim 2, characterized in that a membrane or layer indicates a fault or leak by color change without additional measuring technology.
 22. The package according to claim 1, characterized in that the sensitive element can detect multiparameters.
 23. The package according to claim 22, characterized in that the multiparameters are dependent on concentration, pressure, moisture or temperature.
 24. The package according to claim 2, characterized in that a sensitive membrane or layer has at least one piece of information applied thereto.
 25. The package according to claim 2, characterized in that a sensitive membrane or layer has a least one radio frequency identification (RFI) chip applied thereto or thereon.
 26. The package according to claim 25, characterized in that information is stored and retrievable by electromagnetic waves in the RFI.
 27. The package according to claim 24, characterized in that the information comprises calibrating data, batch information and identifications.
 28. The package according to claim 2, characterized in that the membrane or layer has a signal evaluation unit present thereon.
 29. The package according to claim 28, characterized in that measuring data, control messages are transferable by means of electromagnetic waves and an energy supply is thus effected. 